1. Field of the Invention
The present invention relates in general to a device for conveying and/or distributing fluids with a control handle and, in particular, to a hydraulic valve with ring nut coupling, for example in fluid conveyance and distribution systems.
2. Description of the Related Art
In order to optimise and economise the production of fluid conveyance and distribution systems, such as hydraulic circuits, fitted with pipes and valves of various types, such as distributor valves, flow control valves, drain valves, damping valves, delivery valves or selector valves, the valves are produced normally independently of the pipes and connected to them only at the moment of assembly of the hydraulic circuit.
During the assembly for example of a hydraulic circuit, the valves and pipes are connected to each other in such a way as to permit performance of the desired functions.
To such purpose, the valve usually comprises an externally threaded connection portion and a ring nut with an inner threading, suitable for being screwed onto the connection portion to keep one end of a tube engaged with this connection portion.
This type of connection has the disadvantage that both the tightening of the ring nut during assembly and loosening of the ring nut for maintenance or replacement of the valve require free access to the ring nut so as to be able to grip it with a hand or tightening tool. However, this need for space to assemble and dismantle the valves and flow control devices is generally hard to reconcile with the very limited spaces available in the industrial, civil or military plants which the conveyance and distribution systems are part of. In fact, in most plants, the only freely accessible part of the valve is a control portion of the same such as a handle for regulating the flow through the valve. And it is precisely the control handle which often obstructs access to the connection ring nuts. From EP 1460321A a ball valve with connection ring nut and control handle is known, wherein the control handle can be unmounted from the valve and used as a tool to loosen or tighten the tightening rings to fix the position of a ball shutter inside the valve. The unmounting of the control handle, while in theory permitting improved access to the threaded connection portions and the to the ring nuts, proves time-consuming however and complex as regards the unmounting operations. As a result, the handle of the valve is used practically only to tighten the tightening rings during assembly of the valve, while the dismantling and subsequent reassembly of the handle to the valve body is avoided due to the difficulty of such operations.